Brake Calipers, Do the pistons fit flush inside the caliper ?

the piston has to go back far enough to be flush with the caliper, you can't use a c-clamp on the rear calipers to get it back in place as the piston turns in instead of pushing in, not like the front calipers, go to autozone or any auto store and buy the special tool for rear calipers to be able to get the piston pushed back in properly.